MINING GEOLOGY/Mineral Reserves 625 Table United Nations International Framework Classification for Reserves/Resources Solid fuels and mineral commodities UN International Frame work National system Feasibility study and/ or mining report Prefeasibility study Geological study Detailed exploration General exploration Prospecting Reconnaissance Proved Mineral Reserve (111) Feasibility Mineral Resource (211) Probable Mineral Reserve (121) ỵ (122) Prefeasibility Mineral Resource (221) ỵ (222) Measured Mineral Resource (331) Usually not relevant Usually not relevant Usually not relevant Usually not relevant Usually not relevant Usually not relevant Probable Mineral Reserve (121) ỵ (122) Prefeasibility Mineral Resource (221) ỵ (222) Indicated Mineral Resource (332) Usually not relevant Usually not relevant Usually not relevant Usually not relevant Inferred Mineral Resource (333) ? Reconnaissance Mineral Resource (334) Economic viability categories: economic); ? undetermined economic; potentially economic; economic to potentially economic (intrinsically Figure Schematic illustration of the UN Framework Classification that meets specified minimum physical and chemical criteria related to current mining and production practices, including those of grade, quality, thickness, and depth, is called Reserve Base Reserves are that part of the reserve base which could be economically extracted or produced at the time of determination The whole U.S system of resource/reserve classification is illustrated by Tables and The U.S Resource/Reserve Classification for Minerals seems to be the most widespread, not only in the USA, but in most of world In the classification of the State Commission for Reserves (GKZ) of the Russian Federation reserves and resources are distinguished According to the grade of geological certainty the reserves are divided into the explored ones (categories A, B, C 1), and the estimated ones (category C 2) From the point of view of the economic importance, the reserves are